JP2020049065A - Blood flow measurement device, information processing device, information processing method, and program - Google Patents

Abstract

To provide a new technique for acquiring blood flow information of a living body with a simpler method.SOLUTION: A blood flow measurement device performs blood flow measurement by using optical coherence tomography. The blood flow measurement device includes a data acquisition part, a phase image formation part, an area specification part, a size specification part, and information generation part. The data acquisition part acquires time series data by repeatedly scanning a cross section intersecting with an attention blood vessel of a living body. The phase image formation part forms a plurality of phase images of time series in the cross section based on the time series data. The area specification part specifies the blood vessel area of each of the plurality of phase images formed by the phase image formation part. The size specification part specifies the size of the blood vessel area specified by the area specification part. The information generation part generates information representing a secular change of the size specified by the size specification part about the plurality of phase images.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a blood flow measurement device, an information processing device, an information processing method, and a program.

  Optical coherence tomography (OCT) is used not only for measuring the form of an object but also for measuring its function. For example, an apparatus for measuring a blood flow of a living body using OCT is known. Blood flow measurement using OCT has been applied to blood vessels in the fundus and the like.

  In blood flow measurement using OCT, typically, blood flow information such as blood flow velocity and blood flow is acquired based on time-series data collected by applying OCT to a cross section intersecting a fundus blood vessel. (See, for example, Patent Documents 1 and 2).

JP 2017-079886 A JP 2013-184018 A JP 2009-165710 A Japanese Unexamined Patent Publication No. 2010-523286

  However, in the conventional method, the blood flow information is calculated by analyzing the phase information included in the time-series data acquired using OCT, so that the processing is complicated. Accordingly, there is a demand for acquiring blood flow information by a simpler method.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a new technology for acquiring blood flow information of a living body by a simpler method.

  A first form of some embodiments is a blood flow measurement device that measures a blood flow of a living body using optical coherence tomography. The blood flow measurement device is a data acquisition unit that acquires time-series data by repeatedly scanning a cross section that intersects a target blood vessel of a living body.Based on the time-series data, a plurality of time-series phase images in the cross section are obtained. A phase image forming unit to be formed, a region specifying unit that specifies a blood vessel region in each of the plurality of phase images formed by the phase image forming unit, and a size of the blood vessel region specified by the region specifying unit A size specifying unit that generates the information indicating a temporal change in the size specified by the size specifying unit for the plurality of phase images.

  According to a second aspect of some embodiments, in the first aspect, the information processing apparatus further includes a feature amount calculation unit that calculates a feature amount of the temporal change in the size based on the information generated by the information generation unit.

  In a third aspect of some embodiments, in the second aspect, the feature amount is a period of the temporal change of the size, a difference between a minimum value and a maximum value in the temporal change, the minimum value and the maximum value. And at least one of a time required to change from the minimum value to the maximum value, and a time required to change from the maximum value to the minimum value.

  According to a fourth aspect of some embodiments, in the second aspect or the third aspect, it is determined whether or not the blood vessel of interest is an artery based on a difference between a minimum value and a maximum value in the temporal change. The blood vessel determination unit is included.

  In a fifth aspect of some embodiments, in the fourth aspect, the blood vessel determination unit determines that the blood vessel of interest is an artery when the difference is equal to or greater than a threshold.

  According to a sixth aspect of some embodiments, in any one of the first to fifth aspects, the size specifying unit specifies an area or a perimeter of the blood vessel region specified by the region specifying unit.

  A seventh aspect of some embodiments is based on time-series data obtained by repeatedly scanning a cross section that intersects a target blood vessel of a living body using optical coherence tomography. A phase image forming unit that forms a phase image, a region specifying unit that specifies a blood vessel region in each of the plurality of phase images formed by the phase image forming unit, and a blood vessel region that is specified by the region specifying unit. An information processing apparatus comprising: a size specifying unit that specifies a size; and an information generating unit that generates information indicating a temporal change in the size specified by the size specifying unit for the plurality of phase images.

  An eighth aspect of some embodiments is based on time-series data obtained by repeatedly scanning a cross section that intersects a target blood vessel of a living body using optical coherence tomography. A phase image forming step of forming a phase image, a region specifying step of specifying a blood vessel region in each of the plurality of phase images formed in the phase image forming step, and a blood vessel region specified in the region specifying step. An information processing method, comprising: a size specifying step of specifying a size; and an information generating step of generating information representing a temporal change in the size specified in the size specifying step for the plurality of phase images.

  A ninth aspect of some embodiments is the eighth aspect, further including a feature amount calculating step of calculating a feature amount of the temporal change in the size based on the information generated in the information generating step.

  A tenth aspect of some embodiments is the eighth aspect or the ninth aspect, wherein it is determined whether or not the blood vessel of interest is an artery based on a difference between a minimum value and a maximum value in the temporal change. A blood vessel determination step is included.

  In an eleventh aspect of some embodiments, in the tenth aspect, the blood vessel determination step determines that the blood vessel of interest is an artery when the difference is equal to or greater than a threshold.

  In a twelfth aspect of some embodiments, in any one of the eighth to tenth aspects, the size specifying step specifies an area or a perimeter of the blood vessel region specified in the region specifying step.

  A thirteenth aspect of some embodiments is a program that causes a computer to execute each step of the information processing method described in any of the above.

  In addition, it is possible to arbitrarily combine the configurations according to the plurality of claims described above.

  ADVANTAGE OF THE INVENTION According to this invention, the new technique for acquiring the blood flow information of a living body by a simpler method can be provided.

FIG. 2 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an embodiment. FIG. 2 is a schematic diagram illustrating an example of a configuration of an ophthalmologic apparatus according to an embodiment. It is a schematic diagram for explaining operation of an ophthalmologic apparatus concerning an embodiment. 6 is a flowchart illustrating an example of an operation of the ophthalmologic apparatus according to the embodiment. It is a schematic diagram for explaining operation of an ophthalmologic apparatus concerning an embodiment. It is a schematic diagram for explaining operation of an ophthalmologic apparatus concerning an embodiment. It is a schematic diagram for explaining operation of an ophthalmologic apparatus concerning an embodiment.

  Exemplary embodiments of a blood flow measurement device, an information processing device, an information processing method, and a program according to the present invention will be described in detail with reference to the drawings. In addition, the description content of the literature and any known technology cited in this specification can be used in the following embodiments.

  The blood flow measuring device according to the embodiment has at least a function of executing optical coherence tomography (OCT). In the following embodiment, a case will be described in which the measurement target of the living body is the eye to be inspected (fundus), and an ophthalmologic apparatus that performs Fourier domain type OCT realizes the function of the blood flow measurement apparatus according to the embodiment.

  Hereinafter, an ophthalmologic apparatus combining a swept source OCT and a fundus camera will be described, but the configuration according to the embodiment is not limited to this. For example, the type of OCT is not limited to swept source OCT, but may be spectral domain OCT or the like. Here, the swept source OCT divides light from a wavelength tunable light source (swept wavelength light source) into measurement light and reference light, and superimposes return light of the measurement light from the test object on the reference light to reduce interference light. In this method, the interference light is detected by a balanced photodiode or the like, and the detection data collected in accordance with the sweep of the wavelength and the scanning of the measurement light is subjected to Fourier transform or the like to form an image. On the other hand, the spectral domain OCT divides light from a low coherence light source into measurement light and reference light, and superimposes the return light of the measurement light from the test object with the reference light to generate interference light. Is a method of detecting the spectral distribution of the image by a spectroscope and performing Fourier transform or the like on the detected spectral distribution to form an image. In other words, the swept source OCT is a technique for acquiring a spectrum distribution by time division, and the spectral domain OCT is a technique for acquiring a spectrum distribution by space division. Note that the OCT method applicable to the embodiment is not limited to these, and any other method (for example, time domain OCT) can be applied.

  The ophthalmologic apparatus according to the embodiment may or may not have a function of acquiring a photograph (digital photograph) of the eye to be examined, such as a fundus camera. Further, in place of the fundus camera, an arbitrary modality such as a scanning laser ophthalmoscope (SLO), a slit lamp microscope, an anterior ocular segment photographing camera, or a surgical microscope may be provided. A front image such as a fundus photograph can be used for observation of a fundus, setting of a scan area, tracking, and the like.

<Constitution>
As shown in FIG. 1, the ophthalmologic apparatus 1 includes a fundus camera unit 2, an OCT unit 100, and an arithmetic and control unit 200. The retinal camera unit 2 is provided with an optical system substantially similar to that of a conventional retinal camera. The OCT unit 100 is provided with an optical system and a mechanism for performing OCT. The arithmetic and control unit 200 includes a processor. A chin rest and a forehead support for supporting the face of the subject are provided at a position facing the fundus camera unit 2.

  In this specification, a “processor” is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), an ASIC (Application Specific Integrated Circuit), a programmable logic device (for example, an SPLD (Simple Graphical Programmable Programmable Programmable Logic), or a programmable logic device (for example, an SPLD (Simple Programmable Programmable Programmable Logic Programmable Programmable Logic)). It means a circuit such as a programmable logic device (FPGA) or a field programmable gate array (FPGA). The processor realizes the functions according to the embodiment by, for example, reading and executing a program stored in a storage circuit or a storage device.

<Fundus camera unit 2>
The retinal camera unit 2 is provided with an optical system and a mechanism for photographing the fundus oculi Ef of the eye E to be inspected. Images obtained by photographing the fundus oculi Ef (called fundus images, fundus photographs, and the like) include observation images and photographed images. The observation image is obtained by, for example, moving image shooting using near-infrared light. The captured image is, for example, a color image or a monochrome image obtained using visible flash light, or a monochrome image obtained using near-infrared flash light. The retinal camera unit 2 may be capable of acquiring a fluorescein fluorescent image, an indocyanine green fluorescent image, a spontaneous fluorescent image, and the like.

  The retinal camera unit 2 includes an illumination optical system 10 and a photographing optical system 30. The illumination optical system 10 irradiates the eye E with illumination light. The imaging optical system 30 detects the return light of the illumination light from the eye E to be inspected. The measurement light from the OCT unit 100 is guided to the eye E through an optical path in the fundus camera unit 2, and the return light is guided to the OCT unit 100 through the same optical path.

  The observation light source 11 of the illumination optical system 10 is, for example, a halogen lamp or a light emitting diode (LED). Light (observation illumination light) output from the observation light source 11 is reflected by a reflection mirror 12 having a curved reflection surface, passes through a condenser lens 13, passes through a visible cut filter 14, and is converted into near-infrared light. Become. Further, the observation illumination light is once focused near the imaging light source 15, reflected by the mirror 16, and passes through the relay lenses 17 and 18, the diaphragm 19 and the relay lens 20. Then, the observation illumination light is reflected at the periphery of the perforated mirror 21 (the area around the perforated portion), passes through the dichroic mirror 46, is refracted by the objective lens 22, and passes through the eye E (particularly the fundus Ef). Light up.

  The return light of the observation illumination light from the subject's eye E is refracted by the objective lens 22, passes through the dichroic mirror 46, passes through a hole formed in the central region of the perforated mirror 21, and passes through the dichroic mirror 55. The light is reflected by a mirror 32 via a focusing lens 31. Further, the return light passes through the half mirror 33A, is reflected by the dichroic mirror 33, and is imaged on the light receiving surface of the CCD image sensor 35 by the condenser lens. The CCD image sensor 35 detects return light at a predetermined frame rate, for example. When the focus of the photographing optical system 30 is in focus on the fundus oculi Ef, an observation image of the fundus oculi Ef is obtained, and when the focus is on the anterior eye part, an observation image of the anterior eye part is obtained.

  The imaging light source 15 is, for example, a visible light source including a xenon lamp or an LED. Light (photographing illumination light) output from the photographing light source 15 is applied to the fundus oculi Ef through the same path as the observation illumination light. The return light of the imaging illumination light from the eye E is guided to the dichroic mirror 33 through the same path as the return light of the observation illumination light, passes through the dichroic mirror 33, is reflected by the mirror 36, and is reflected by the condenser lens 37. An image is formed on the light receiving surface of the CCD image sensor 38.

  The liquid crystal display (LCD) 39 displays a fixation target for fixing the eye E to be examined. A part of the light flux (fixation light flux) output from the LCD 39 is reflected by the half mirror 33A, is reflected by the mirror 32, passes through the imaging focusing lens 31 and the dichroic mirror 55, and passes through the aperture of the apertured mirror 21. Through the department. The fixation light beam that has passed through the aperture of the apertured mirror 21 passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected on the fundus Ef. By changing the display position of the fixation target on the screen of the LCD 39, the fixation position of the eye E can be changed. Note that, instead of the LCD 39, a matrix LED in which a plurality of LEDs are two-dimensionally arranged, a combination of a light source and a variable stop (a liquid crystal stop, or the like), or the like can be used as a fixation light beam generating unit.

  The fundus camera unit 2 is provided with an alignment optical system 50 and a focus optical system 60. The alignment optical system 50 generates an alignment index used for alignment of the optical system with the eye E. The focus optical system 60 generates a split index used for focus adjustment on the eye E.

  The alignment light output from the LED 51 of the alignment optical system 50 passes through the apertures 52 and 53 and the relay lens 54, is reflected by the dichroic mirror 55, and passes through the hole of the perforated mirror 21. The light that has passed through the hole of the perforated mirror 21 passes through the dichroic mirror 46 and is projected onto the eye E by the objective lens 22.

  The corneal reflected light of the alignment light passes through the objective lens 22, the dichroic mirror 46, and the above-mentioned hole, a part of which passes through the dichroic mirror 55, passes through the imaging focusing lens 31, is reflected by the mirror 32, and is reflected by the mirror 32. The light passes through the mirror 33A, is reflected by the dichroic mirror 33, and is projected on the light receiving surface of the CCD image sensor 35 by the condenser lens. Based on the light reception image (the alignment index image composed of two luminescent spots) by the CCD image sensor 35, the same manual alignment and automatic alignment as in the related art can be performed.

  The focus optical system 60 is moved along the optical path (illumination optical path) of the illumination optical system 10 in conjunction with the movement of the imaging focusing lens 31 along the optical path (illumination optical path) of the imaging optical system 30. The reflection bar 67 is insertable into and removable from the illumination optical path.

  When performing the focus adjustment, the reflection surface of the reflection bar 67 is obliquely provided in the illumination optical path. Focus light output from the LED 61 passes through a relay lens 62, is split into two light beams by a split optotype plate 63, passes through a two-hole stop 64, is reflected by a mirror 65, and is reflected by a condensing lens 66 through a reflecting rod. The image is once formed on the reflecting surface 67 and reflected. Further, the focus light passes through the relay lens 20, is reflected by the aperture mirror 21, passes through the dichroic mirror 46, is refracted by the objective lens 22, and is projected on the fundus Ef.

  The fundus reflected light of the focus light is detected by the CCD image sensor 35 through the same path as the corneal reflected light of the alignment light. Based on the light reception image (a split index image composed of two bright line images) by the CCD image sensor 35, the same manual alignment and automatic alignment as in the related art can be performed.

  The dichroic mirror 46 combines the optical path for fundus imaging and the optical path for OCT. The dichroic mirror 46 reflects light in a wavelength band used for OCT and transmits light for fundus imaging. In the OCT optical path, a collimator lens unit 40, an optical path length changing unit 41, an optical scanner 42, an OCT focusing lens 43, a mirror 44, and a relay lens 45 are provided in this order from the OCT unit 100 side.

  The optical path length changing unit 41 is movable in the direction of the arrow shown in FIG. 1 and changes the optical path length of the OCT optical path. This change in the optical path length is used for correcting the optical path length according to the axial length of the eye E, adjusting the interference state, and the like. The optical path length changing unit 41 includes, for example, a corner cube and a mechanism for moving the corner cube.

  The optical scanner 42 is disposed at a position optically conjugate with the pupil of the eye E to be examined. The optical scanner 42 changes the traveling direction of the measurement light LS passing through the OCT optical path. Thereby, the eye E is scanned with the measurement light LS. The optical scanner 42 can deflect the measurement light LS in an arbitrary direction on the xy plane, and includes, for example, a galvanomirror that deflects the measurement light LS in the x direction and a galvanomirror that deflects the measurement light LS in the y direction.

<OCT unit 100>
As illustrated in FIG. 2, the OCT unit 100 is provided with an optical system for performing OCT of the eye E to be inspected. The configuration of this optical system is the same as that of the conventional swept source OCT. That is, this optical system divides light from the light source into measurement light and reference light, and generates interference light by superimposing the return light of the measurement light from the eye E and the reference light via the reference optical path. And an interference optical system for detecting the interference light. The detection result (detection signal) obtained by the interference optical system is a signal indicating the spectrum of the interference light, and is sent to the arithmetic and control unit 200.

  The light source unit 101 includes a wavelength variable light source capable of changing the wavelength of emitted light at high speed, similarly to a general swept source OCT. The wavelength variable light source is, for example, a near-infrared laser light source.

  The light L0 output from the light source unit 101 is guided to a polarization controller 103 by an optical fiber 102, and its polarization state is adjusted. Further, the light L0 is guided to the fiber coupler 105 by the optical fiber 104 and split into the measurement light LS and the reference light LR.

  The reference light LR is guided by an optical fiber 110 to a collimator 111, converted into a parallel light flux, and guided to a corner cube 114 via an optical path length correction member 112 and a dispersion compensation member 113. The optical path length correction member 112 acts to match the optical path length of the reference light LR with the optical path length of the measurement light LS. The dispersion compensating member 113 acts to match the dispersion characteristics between the reference light LR and the measurement light LS.

  The corner cube 114 turns the traveling direction of the incident reference light LR in the opposite direction. The incident direction and the outgoing direction of the reference light LR with respect to the corner cube 114 are parallel to each other. The corner cube 114 is movable in the direction of incidence of the reference light LR, thereby changing the optical path length of the reference light LR.

  1 and 2, the optical path length changing unit 41 for changing the length of the optical path (measurement optical path, measurement arm) of the measurement light LS, and the optical path (reference optical path, reference arm) of the reference light LR. Although both the corner cubes 114 for changing the length are provided, only one of the optical path length changing unit 41 and the corner cube 114 may be provided. It is also possible to change the difference between the measured optical path length and the reference optical path length by using other optical members.

  The reference light LR that has passed through the corner cube 114 passes through the dispersion compensating member 113 and the optical path length correcting member 112, is converted from a parallel light beam into a focused light beam by the collimator 116, and enters the optical fiber 117. The reference light LR that has entered the optical fiber 117 is guided to the polarization controller 118 to adjust its polarization state, is guided to the attenuator 120 by the optical fiber 119, adjusts the light amount, and is guided to the fiber coupler 122 by the optical fiber 121. I will

  On the other hand, the measurement light LS generated by the fiber coupler 105 is guided by the optical fiber 127 and converted into a parallel light flux by the collimator lens unit 40, and is changed into an optical path length changing unit 41, an optical scanner 42, an OCT focusing lens 43, and a mirror 44. Then, the light is reflected by the dichroic mirror 46 via the relay lens 45, refracted by the objective lens 22, and enters the eye E to be examined. The measurement light LS is scattered and reflected at various depth positions of the eye E. The return light of the measurement light LS from the subject's eye E travels in the same path as the outward path in the opposite direction, is guided to the fiber coupler 105, and reaches the fiber coupler 122 via the optical fiber 128.

  The fiber coupler 122 generates interference light by superimposing the measurement light LS input via the optical fiber 128 and the reference light LR input via the optical fiber 121. The fiber coupler 122 generates a pair of interference lights LC by splitting the interference light at a predetermined split ratio (for example, 1: 1). The pair of interference lights LC is guided to the detector 125 through the optical fibers 123 and 124, respectively.

  The detector 125 is, for example, a balanced photodiode (Balanced Photo Diode). The balanced photodiode has a pair of photodetectors for detecting a pair of interference lights LC, respectively, and outputs a difference between detection results obtained by the pair of photodetectors. The detector 125 sends the detection result (detection signal) to a DAQ (Data Acquisition System) 130.

  The DAQ 130 is supplied with a clock KC from the light source unit 101. The clock KC is generated in the light source unit 101 in synchronization with the output timing of each wavelength swept within a predetermined wavelength range by the variable wavelength light source. The light source unit 101, for example, optically delays one of the two branched lights obtained by branching the light L0 of each output wavelength, and then generates the clock KC based on the result of detecting the combined light. Generate. The DAQ 130 samples the detection signal input from the detector 125 based on the clock KC. The DAQ 130 sends a sampling result of the detection signal from the detector 125 to the arithmetic and control unit 200.

<Arithmetic control unit 200>
The arithmetic and control unit 200 controls each unit of the fundus camera unit 2, the display device 3, and the OCT unit 100. In addition, the arithmetic and control unit 200 executes various arithmetic processes. For example, the arithmetic and control unit 200 performs signal processing such as Fourier transform on a spectral distribution based on a detection result obtained by the detector 125 for each series of wavelength scans (for each A line), thereby obtaining a signal for each A line. Form a reflection intensity profile. Further, the arithmetic and control unit 200 forms image data by imaging the reflection intensity profile of each A line. The arithmetic processing for that is the same as in the conventional swept source OCT.

  The arithmetic and control unit 200 includes, for example, a processor, a RAM (Random Access Memory), a ROM (Read Only Memory), a hard disk drive, a communication interface, and the like. Various computer programs are stored in a storage device such as a hard disk drive. The arithmetic and control unit 200 may include an operation device, an input device, a display device, and the like.

<Control system>
The control system (processing system) of the ophthalmologic apparatus 1 is mainly configured by the arithmetic and control unit 200.

  3 to 5 show configuration examples of a control system (processing system) of the ophthalmologic apparatus 1. FIG. 3 illustrates an example of a functional block diagram of a control system of the ophthalmologic apparatus 1. FIG. 4 illustrates an example of a functional block diagram of the image forming unit 220 in FIG. FIG. 5 illustrates an example of a functional block diagram of the data processing unit 230 in FIG.

  As shown in FIG. 3, the arithmetic and control unit 200 includes a control unit 210, an image forming unit 220, and a data processing unit 230.

<Control unit 210>
The control unit 210 controls each unit of the ophthalmologic apparatus 1. The control unit 210 includes a processor, a RAM, a ROM, a hard disk drive, and the like. The function of the control unit 210 is realized by cooperation between hardware including a circuit and control software. Control unit 210 includes a main control unit 211 and a storage unit 212.

<Main control unit 211>
The main control unit 211 performs various controls. In particular, the main control unit 211 controls the focus driving units 31A and 43A, the CCD image sensors 35 and 38, the LCD 39, the optical path length changing unit 41, and the optical scanner 42 of the fundus camera unit 2. Further, the main control unit 211 controls the light source unit 101, the reference drive unit 114A, the detector 125, the DAQ 130, and the like of the OCT unit 100. Further, the main control unit 211 controls an optical system driving unit (not shown) that drives the optical system shown in FIGS.

  The focus drive unit 31 </ b> A moves the imaging focus lens 31 along the optical axis of the imaging optical system 30 under the control of the main control unit 211. The focusing drive unit 31A is provided with a holding member that holds the photographing focusing lens 31, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears and a rack and pinion. As a result, the focusing drive unit 31A controlled by the main control unit 211 moves the imaging focusing lens 31, thereby changing the focusing position of the imaging optical system 30. Note that the focusing drive unit 31 </ b> A may move the focusing lens 31 along the optical axis of the imaging optical system 30 manually or by an operation on the operation unit 242 by the user.

  The focus driving unit 43A moves the OCT focusing lens 43 along the optical axis (optical path of the measurement light) of the interference optical system in the OCT unit 100 under the control of the main control unit 211. The focusing drive unit 43A includes a holding member that holds the OCT focusing lens 43, an actuator that generates a driving force for moving the holding member, and a transmission mechanism that transmits the driving force. The actuator is constituted by, for example, a pulse motor. The transmission mechanism is composed of, for example, a combination of gears and a rack and pinion. Thereby, the focus drive unit 43A controlled by the main control unit 211 moves the OCT focus lens 43, thereby changing the focus position of the measurement light. Note that the focusing drive unit 43A may move the OCT focusing lens 43 along the optical axis of the interference optical system manually or by an operation on the operation unit 242 by the user.

  The main control unit 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, and the like of the CCD image sensor 35. The main control section 211 can control the exposure time, sensitivity, frame rate, and the like of the CCD image sensor 38.

  The main control unit 211 can control display of the fixation target and the visual acuity measurement target on the LCD 39. Thereby, it is possible to switch the target presented to the eye E and change the type of the target. Further, by changing the display position of the optotype on the LCD 39, the optotype presenting position with respect to the eye E can be changed.

  By controlling the optical path length changing unit 41, the main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS. The main control unit 211 controls the optical path length changing unit 41 so that the target portion of the eye E is drawn in a predetermined range in the frame of the OCT image. Specifically, the main control unit 211 controls the optical path length changing unit 41 so that the target portion of the subject's eye E is drawn at a predetermined z position (a position in the depth direction) within the frame of the OCT image. Is possible.

  The main control unit 211 can change the scanning position of the measurement light LS in the fundus oculi Ef of the eye E or the anterior segment by controlling the optical scanner 42. The control of the optical scanner 42 includes controlling the scanning position, scanning range, or scanning speed by a galvanomirror that deflects the measurement light LS in the x direction, and scanning position, scanning range, or scanning by a galvanomirror that deflects the measurement light LS in the y direction. There is speed control. Further, the main control unit 211 can control the scanning mode of the measurement light LS by the optical scanner 42. Examples of the scanning mode of the measurement light LS include a horizontal scan, a vertical scan, a cross scan, a radiation scan, a circle scan, a concentric scan, and a spiral scan.

  By controlling the light source unit 101, the main control unit 211 can control switching between turning on and off the light L0, changing the amount of light L0, and the like.

  By controlling the reference drive unit 114A, the main control unit 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS. The reference drive unit 114A moves the corner cube 114 provided on the reference optical path. Thereby, the length of the reference light path is changed. The main control unit 211 controls the reference driving unit 114A so that the target part of the eye E is drawn in a predetermined range in the frame of the OCT image. Specifically, the main control unit 211 can control the reference driving unit 114A so that the target portion of the eye E is drawn at a predetermined z position in the frame of the OCT image. The main controller 211 can relatively change the difference between the optical path length of the reference light LR and the optical path length of the measurement light LS by controlling at least one of the optical path length changing unit 41 and the reference driving unit 114A. It is. Hereinafter, the main control unit 211 will be described as adjusting the optical path length difference between the measurement light LS and the reference light LR by controlling only the optical path length changing unit 41. However, the main control unit 211 controls only the reference drive unit 114A. May be used to adjust the optical path length difference between the reference light LR and the measurement light LS.

  The main control unit 211 can control the exposure time (charge accumulation time), sensitivity, frame rate, and the like of the detector 125. Further, the main control unit 211 can control the DAQ 130.

  An optical system driving unit (not shown) three-dimensionally moves the optical system (the optical system shown in FIGS. 1 and 2) provided in the ophthalmologic apparatus 1. The main control unit 211 can control the optical system driving unit so as to maintain the positional relationship between the subject's eye E and the apparatus optical system. This control is used in alignment and tracking. The tracking is to move the apparatus optical system in accordance with the movement of the eye E. When performing tracking, alignment and focusing are performed in advance. In tracking, the apparatus optical system is moved in real time in accordance with the position and orientation of the eye E based on an image obtained by capturing a moving image of the eye E to maintain a suitable positional relationship where alignment and focus are achieved. Function.

<Storage unit 212>
The storage unit 212 stores various data. The data stored in the storage unit 212 includes, for example, image data of an OCT image, image data of a fundus image, eye information of an examinee, and the like. The subject eye information includes subject information such as a patient ID and a name, left eye / right eye identification information, electronic medical record information, and the like.

<Image forming unit 220>
The image forming unit 220 forms image data of a tomographic image of the fundus oculi Ef and image data of a phase image based on the detection signal from the detector 125 sampled by the DAQ 130. Image forming section 220 includes a processor. In this specification, “image data” and “image” based on the image data may be identified.

  As shown in FIG. 4, the image forming unit 220 includes a tomographic image forming unit 221 and a phase image forming unit 222.

<Tomographic image forming unit 221>
The tomographic image forming unit 221 forms image data of a tomographic image of the fundus oculi Ef based on the sampling result of the detection signal by the DAQ 130. This processing includes signal processing such as noise removal (noise reduction), filter processing, and fast Fourier transform (FFT), similarly to the conventional swept source OCT. The image data formed by the tomographic image forming unit 221 is a group of image data formed by imaging reflection intensity profiles on a plurality of A lines (scan lines along the z direction) arranged along the scan lines. This is a data set including (a group of A-scan image data).

<Phase image forming unit 222>
The phase image forming unit 222 forms a phase image based on data (OCT data) obtained by repeatedly performing an OCT scan on a predetermined portion of the fundus oculi Ef. In this embodiment, time-series data (time-series OCT data) is obtained by repeatedly scanning (OCT scanning) a predetermined part of the fundus oculi Ef. The period repeatedly scanned may be a period including at least the diastole and the systole of the heart of the living body. The predetermined site includes a target blood vessel. The OCT scan is performed so as to intersect the blood vessel of interest at a predetermined site.

  The phase image forming unit 222 forms a phase image of a cross section that intersects a target blood vessel at a predetermined site based on each of the acquired time-series data. That is, based on the time-series data acquired by repeatedly scanning the predetermined portion of the fundus oculi Ef with the measurement light LS, the phase image forming unit 222 generates a plurality of time-series phase images in a cross section of the predetermined portion. Form.

  Data used for forming a phase image may be the same as data used for forming a tomographic image by the tomographic image forming unit 221. In this case, the tomographic image of the scanned cross section and the phase image can be easily aligned. That is, the tomographic image and the phase image formed based on the same data can naturally associate the tomographic image pixel with the phase image pixel.

  An example of a method for forming a phase image will be described. The phase image in this example is obtained by calculating the phase difference between adjacent A-line complex signals (signals corresponding to adjacent scanning points). In other words, the phase image of the present example is formed for each pixel of the scanned tomographic image on the basis of the time-series change of the pixel value (luminance value) of the pixel. For an arbitrary pixel, the phase image forming unit 222 considers a graph of a time-series change in the luminance value. The phase image forming unit 222 calculates a phase difference Δφ between two time points t1 and t2 (t2 = t1 + Δt) separated by a predetermined time interval Δt in this graph. Then, this phase difference Δφ is defined as the phase difference Δφ (t1) at the time point t1 (more generally, any time point between the two time points t1 and t2). By performing this processing at each of a large number of preset time points, a time-series change in the phase difference at the pixel is obtained.

  The phase image expresses the value of the phase difference of each pixel at each point in time as an image. This imaging process can be realized, for example, by expressing the value of the phase difference with a display color or luminance. At this time, the color (for example, red) indicating that the phase has increased along the time series can be different from the color (for example, blue) that indicates that the phase has decreased. In addition, the magnitude of the phase change amount can be expressed by the display color density. By employing such an expression method, it is possible to present the direction and size of the blood flow in color and density. A phase image is formed by executing the above processing for each pixel.

  The time-series change of the phase difference can be obtained by making the time interval Δt sufficiently small to secure the phase correlation. At this time, oversampling in which the time interval Δt is set to a value less than the time corresponding to the resolution of the tomographic image in the scanning of the measurement light LS is performed.

<Data processing unit 230>
The data processing section 230 performs various data processing (image processing) and analysis processing on the image data formed by the image forming section 220. For example, the data processing unit 230 executes correction processing such as luminance correction and dispersion correction of the image. In addition, the data processing unit 230 performs various image processing and analysis processing on images (anterior eye images and the like) obtained using the CCD image sensors 35 and 38.

  The data processing unit 230 can form volume data (voxel data) of the eye E by performing known image processing such as interpolation processing for interpolating pixels between tomographic images. When displaying an image based on the volume data, the data processing unit 230 performs a rendering process on the volume data to form a pseudo three-dimensional image when viewed from a specific viewing direction.

  The data processing unit 230 performs various renderings on the acquired volume data (three-dimensional data set, stack data, and the like), and thereby performs a B-mode image (vertical cross-sectional image, axial cross-sectional image) on an arbitrary cross section, A C-mode image (transverse cross-sectional image, horizontal cross-sectional image), a projection image, a shadowgram, and the like can be formed. An image of an arbitrary cross section such as a B-mode image or a C-mode image is formed by selecting a pixel (pixel, voxel) on a specified cross section from a three-dimensional data set. The projection image is formed by projecting the three-dimensional data set in a predetermined direction (z direction, depth direction, axial direction). The shadowgram is formed by projecting a part of the three-dimensional data set (for example, partial data corresponding to a specific layer) in a predetermined direction. An image, such as a C-mode image, a projection image, or a shadowgram, which is viewed from the front side of the subject's eye is referred to as a front image (en-face image).

  In addition, the data processing unit 230 performs a B-mode image in which retinal blood vessels and choroidal blood vessels are enhanced and a frontal image (blood vessel enhanced image, angio-based image, etc.) based on data (for example, B-scan image data) collected in time series by OCT. G) can be constructed. For example, time-series OCT data can be collected by repeatedly scanning substantially the same site of the eye E.

  In some embodiments, the data processing unit 230 compares the time-series B-scan images obtained by the B-scan for substantially the same part, and converts the pixel value of the portion where the signal intensity changes to a pixel value corresponding to the change. By performing the conversion, an emphasized image in which the changed portion is emphasized is constructed. Further, the data processing unit 230 forms an OCT angiogram by extracting information of a predetermined thickness at a desired site from the constructed plurality of emphasized images and constructing the information as an en-face image.

  The data processing unit 230 according to the embodiment can generate blood flow information based on a plurality of time-series phase images formed by the phase image forming unit 222. As shown in FIG. 5, the data processing unit 230 includes a blood vessel region specifying unit 231, a blood vessel region size specifying unit 232, an information generating unit 233, a feature amount calculating unit 234, and a blood vessel determining unit 235. Including.

<Vascular region specifying unit 231>
The blood vessel region specifying unit 231 specifies a blood vessel region (a cross-sectional region of the target blood vessel) corresponding to the target blood vessel in the phase image formed by the phase image forming unit 222. In this embodiment, the blood vessel region specifying unit 231 specifies a blood vessel region in each of a plurality of phase images formed by the phase image forming unit 222 based on the time-series data. The blood vessel region is specified by specifying a region where the change in the phase difference is large.

  In some embodiments, the vascular region specifying unit 231 specifies a vascular region by analyzing pixel values of a phase image. This analysis processing includes, for example, known image processing such as threshold processing, edge detection, binarization, thinning, and area growing (region growing).

  In some embodiments, when the shape of the blood vessel region depicted in the phase image is substantially circular, the blood vessel region specifying unit 231 specifies the substantially circular region where the change in the phase difference is large. To identify.

  In this embodiment, it is possible to form a tomographic image and a phase image from the same data. Thereby, the blood vessel region specifying unit 231 specifies the blood vessel region in the tomographic image in which the cross-sectional morphology is drawn relatively clearly, and specifies the region in the phase image corresponding to the specified blood vessel region as the blood vessel region. Is possible.

  In some embodiments, the vascular region specifying unit 231 specifies the specified vascular region based on the content of an operation performed on the operation unit 242 (described later) by the user. The user operates the operation unit 242 while viewing the front image or the cross-sectional phase image of the fundus oculi Ef displayed on the display unit 241 (described later) by the main control unit 211, thereby corresponding to the desired blood vessel of interest. A blood vessel region can be specified.

<Vessel region size specifying unit 232>
The blood vessel region size specifying unit 232 specifies the size of the blood vessel region in the phase image specified by the blood vessel region specifying unit 231. Examples of the size of the blood vessel region include an area and a circumference of the blood vessel region, a diameter or radius when the region is approximated by a circle, and a major axis and a minor axis when the region is approximated by an ellipse.

  The process of specifying the area includes, for example, a process of counting the number of pixels in the specified region. The process of specifying the perimeter includes, for example, a process of counting the number of pixels included in the outer edge of the specified region. The process of specifying the diameter and the like when the region is approximated by a circle includes a process of specifying the outline of the specified region, a process of calculating an approximate circle of the specified outline by a known circle approximation process, and a process of calculating the approximate circle. Specifying the diameter or radius of the approximate circle. The process of specifying the major axis and the like when the region is approximated by an ellipse includes a process of specifying the outline of the specified region, a process of calculating the approximated ellipse by a known ellipse approximation process of the specified outline, and Specifying a major axis and a minor axis of the approximate ellipse.

  In this embodiment, the vascular region size specifying unit 232 specifies the size of the vascular region in each of the plurality of phase images specified by the vascular region specifying unit 231.

<Information generator 233>
The information generating unit 233 generates information representing a temporal change in the size specified by the blood vessel region size specifying unit 232 for a plurality of phase images. The information generation unit 233, for example, compares the size specified by the vascular region size specifying unit 232 with the corresponding vascular region in the phase image and the OCT data acquisition timing (OCT scan execution timing) for forming the phase image. ) Is stored in a storage unit (or storage unit 212) (not shown). The information generation unit 233 generates information indicating a temporal change in the size of the blood vessel region corresponding to the target blood vessel, based on the size and the acquisition timing associated with the blood vessel region corresponding to the desired target blood vessel.

  As information representing a temporal change in the size of the blood vessel region, a horizontal axis (vertical axis) represents time, and a vertical axis (horizontal axis) represents a temporal change graph representing the size of the area of the blood vessel region, the area of the blood vessel region, and the like. There is a list that arranges the sizes of the chronological order. The main control unit 211 can cause the display unit 241 to display the temporal change information generated by the information generation unit 233.

<Feature amount calculation unit 234>
The feature amount calculation unit 234 calculates a feature amount of the size change over time based on the information indicating the size change over time generated by the information generation unit 233. It is possible to obtain blood flow information and the like of the blood vessel region based on the calculated feature amount.

  FIG. 6 schematically illustrates an example of information indicating a temporal change in size generated by the information generating unit 233 according to the embodiment. In FIG. 6, an example of a temporal change graph representing the time on the horizontal axis and the area (unit: number of pixels) of the blood vessel region on the vertical axis is represented by a broken line. In FIG. 6, a solid line representing a temporal change of a blood flow velocity (blood flow velocity) (unit: millimeter per second) is shown together with a temporal change of the area of the blood vessel region. For example, as disclosed in Japanese Patent Application Laid-Open No. 2017-079886, the temporal change in blood flow velocity is analyzed by analyzing phase information included in time-series data acquired by OCT performed on the fundus oculi Ef. It is required by In FIG. 6, the temporal change of the blood flow velocity thus obtained is shown on the same time axis as the temporal change of the area of the blood vessel region.

  As shown in FIG. 6, as the blood flow velocity increases with time, the area of the blood vessel region in the phase image increases, and as the blood flow velocity decreases with time, the area of the blood vessel region decreases. In addition, the change timing of the area of the blood vessel region (rise timing, fall timing, cycle, etc.) substantially coincides with the change timing of the blood flow velocity. That is, there is a correlation between the temporal change of the area of the blood vessel region and the temporal change of the blood flow velocity obtained by analyzing the phase information. By paying attention to this correlation, by calculating a feature amount of information representing a temporal change of the size of the blood vessel region generated by the information generating unit 233, a complicated process for analyzing phase information is not performed. It is possible to specify the blood flow information of the blood vessel of interest.

  The characteristic amount calculated by the characteristic amount calculation unit 234 is based on information indicating the temporal change of the area (size), based on the period T of the temporal change of the area, the minimum value Min and the maximum value Max in the temporal change. At least one of a difference D, a ratio R between the minimum value Min and the maximum value Max, a time T1 required to change from the minimum value Min to the maximum value Max, and a time T2 required to change from the maximum value Max to the minimum value Min. including. In some embodiments, the feature value calculated by the feature value calculation unit 234 further includes at least one of an average value of the size, a difference between the average value and the minimum value, and a difference between the average value and the maximum value. Including. The same applies to a case where the size is another parameter such as a peripheral length other than the area.

  The change over time in blood flow velocity is a change due to the heartbeat. The cycle T is calculated as a feature amount of the temporal change in the size of the blood vessel region in the phase image, and the heart rate of the subject is specified by, for example, converting the calculated cycle T into the number of beats per minute. It becomes possible.

  In an artery, the difference between the minimum value and the maximum value in the temporal change of the blood flow velocity is large, whereas in the vein, the difference between the minimum value and the maximum value in the temporal change in the blood flow velocity is very small. The difference D is calculated as a feature amount of the temporal change of the size of the blood vessel region in the phase image, and the magnitude of the calculated difference D is analyzed to determine whether the target blood vessel corresponding to the blood vessel region is an artery or a vein. It is possible to determine whether or not.

  Further, in arteriosclerosis, the ratio of the minimum value to the maximum value (for example, the maximum value / minimum value) in the temporal change of the blood flow velocity is smaller than that in a normal blood vessel. By calculating a ratio R between the minimum value Min and the maximum value Max as a feature amount of the temporal change in the size of the blood vessel region in the phase image, and analyzing the magnitude of the calculated ratio R, attention corresponding to the blood vessel region is obtained. It is possible to determine whether or not a blood vessel is suspected of arteriosclerosis (circulatory disease).

  In addition, when there is an abnormality in the heart valve, the time required for the blood flow velocity to change from the minimum value to the maximum value over time increases. The time T1 at which the minimum value Min changes from the minimum value Min to the maximum value Max is calculated as a characteristic amount of the temporal change of the size of the blood vessel region in the phase image, and the length of the calculated time T1 is analyzed. It is possible to determine whether or not there is. In particular, when the blood vessel of interest is an artery, the cycle T can be calculated. Therefore, a time T2 at which the maximum value Max changes to the minimum value Min is calculated as a feature amount of the temporal change in the size of the blood vessel region in the phase image. You may do so.

  Further, it is also possible to estimate the blood flow velocity from the difference D calculated as a feature amount of the temporal change in the size of the blood vessel region in the phase image. For example, when the reference value (normal data) of the blood flow velocity corresponding to the size of the blood vessel region in the phase image specified by the blood vessel region size specifying unit 232 is known, the blood flow speed is calculated from the difference D based on the reference value. (Minimum value, maximum value) can be estimated.

  In some embodiments, the target blood vessel is classified into any of a plurality of speed ranges based on the difference D calculated as the feature amount. When the range of the difference between the minimum value and the maximum value of the size change over time for each speed range is determined in advance, it is determined which of the plurality of speed ranges the difference D calculated as the feature amount falls into. can do. The control unit 210 (main control unit 211) can cause the display unit 241 to display a blood vessel region corresponding to the blood vessel of interest in the fundus image or the OCT angiogram so that the classified speed range can be identified.

<Vessel determination unit 235>
The blood vessel determination unit 235 determines whether the target blood vessel corresponding to the blood vessel region is an artery, based on the feature amount calculated by the feature amount calculation unit 234 as described above. As described above, the blood vessel determination unit 235 compares the difference D between the minimum value Min and the maximum value Max with a predetermined threshold value, and when the difference D is equal to or greater than the threshold value, the target blood vessel corresponding to the blood vessel region is determined. It is determined that the blood vessel is an artery, and when the difference D is less than the threshold value, it is determined that the target blood vessel corresponding to the blood vessel region is a vein.

  In some embodiments, it is determined whether or not the blood vessel of interest is an artery in consideration of the cycle T in addition to the comparison result between the difference D and the threshold.

<User interface 240>
The ophthalmologic apparatus 1 is provided with a user interface 240. The user interface 240 includes a display unit 241 and an operation unit 242. The display unit 241 includes the display device 3. The operation unit 242 includes various operation devices and input devices. The user interface 240 may include a device in which a display function and an operation function are integrated, such as a touch panel, for example. Embodiments that do not include at least a portion of the user interface 240 can also be constructed. For example, the display device may be an external device connected to the ophthalmic device.

  The ophthalmologic apparatus 1 is an example of the “blood flow measuring device” according to the embodiment. The arithmetic and control unit 200 is an example of the “information processing device” according to the embodiment. The fundus oculi Ef (the eye E) is an example of the “living body” according to the embodiment. In FIG. 1, the optical system from the objective lens 22 to the OCT unit 100 and the arithmetic and control unit 200 are examples of a “data acquisition unit” according to the embodiment. The blood vessel region specifying unit 231 is an example of the “region specifying unit” according to the embodiment. The blood vessel region size specifying unit 232 is an example of the “size specifying unit” according to the embodiment.

<motion>
An operation of the ophthalmologic apparatus 1 according to the embodiment will be described.

  An example of the operation of the ophthalmologic apparatus 1 is shown in FIG. The storage unit 212 stores a computer program for implementing the processing illustrated in FIG. The main control unit 211 executes the processing shown in FIG. 7 by operating according to the computer program. It is assumed that general preparation processing such as alignment, focus adjustment, interference sensitivity adjustment, and z position adjustment has already been completed.

(S1: 3D scan)
First, the control unit 210 (main control unit 211) controls the OCT unit 100 and the like to execute a three-dimensional scan for OCT angiography on the fundus oculi Ef. For example, for a plurality of sites of the fundus oculi Ef, time-series OCT data is collected by repeatedly performing an OCT scan on substantially the same site.

(S2: Frontal angiographic image is formed)
The data processing unit 230 compares the time-series B-scan images obtained by the B-scan for substantially the same part, and converts the pixel values of at least one portion where the signal intensity and the phase change into pixel values corresponding to the change. Thus, an emphasized image in which the changed portion is emphasized is constructed. Further, the data processing unit 230 extracts information of a predetermined thickness at a desired portion from the constructed plurality of emphasized images and constructs the information as an en-face image to thereby generate a frontal angiographic image (OCT angiogram). Form.

(S3: Designate target vessel)
The control unit 210 receives an operation performed on the operation unit 242 by the user, and receives a 1 in the blood vessel distribution expressed in the front angiographic image (or the fundus image acquired using the fundus camera unit 2) formed in step S2. The above-mentioned designation of the blood vessel of interest is received.

  In some embodiments, the data processing unit 230 specifies a blood vessel having a predetermined diameter or more among the blood vessels depicted in the front angiographic image formed in step S2. The control unit 210 designates one or more blood vessels specified by the data processing unit 230 as a target blood vessel.

  The following processing is applied to each of the designated vessels of interest.

(S4: Collect time series data)
The control unit 210 extracts, from the OCT data obtained in step S1, time-series OCT data obtained by repeatedly performing OCT on a cross section that intersects with the target blood vessel specified in step S3. And collect the desired time series data.

  The control unit 210 may control the OCT unit 100 to repeatedly scan a cross section intersecting the target blood vessel designated in step S3, and may acquire time-series OCT data.

(S5: forming a phase image)
The image forming unit 220 forms a plurality of phase images of a cross section intersecting the target blood vessel specified in step S3 based on each of the time-series OCT data collected in step S4.

(S6: Specify blood vessel region)
The blood vessel region specifying unit 231 specifies a blood vessel region for each of the plurality of phase images formed in step S5.

(S7: Specify the area of the blood vessel region)
The blood vessel region size specifying unit 232 specifies the area of each of the one or more blood vessel regions formed in step S6.

  In some embodiments, the vascular region size specifying unit 232 specifies a perimeter for each of the one or more vascular regions formed in step S6.

(S8: Generate information indicating a change over time)
The information generation unit 233 generates information indicating a temporal change in the area (perimeter) specified in step S7.

(S9: Calculate feature amount)
The feature amount calculation unit 234 calculates the difference between the minimum value and the maximum value of the area of the blood vessel region as the feature amount from the information indicating the change over time in the area of the blood vessel region generated in step S8.

(S10: blood vessel determination)
The blood vessel determination unit 235 compares the difference as the feature amount calculated in step S9 with a predetermined threshold, determines that the target blood vessel is an artery when the difference is equal to or greater than the threshold, and determines that the difference is a threshold. When the value is less than, it is determined that the target blood vessel is a vein. Step S10 is executed for each blood vessel of interest for which the characteristic amount has been calculated in step S9.

(S11: judgment result is displayed)
The control unit 210 causes the display unit 241 to display the front angiographic image formed in step S2 and the determination result obtained in step S10.

  The control unit 210 can display information indicating the target blood vessel specified in step S3 together with the front angiographic image. As a typical example, the control unit 210 displays an image area corresponding to a target blood vessel in a front angiographic image in a predetermined color. For example, a blood vessel of interest determined to be an artery can be displayed in red, and a blood vessel of interest determined to be a vein can be displayed in blue.

  When two or more blood vessels of interest are designated, different colors can be assigned to a plurality of image regions corresponding to these blood vessels of interest. At this time, the target blood vessel determined to be an artery can be displayed in a warm color, and the target blood vessel determined to be a vein can be displayed in a cool color.

  This is the end of the operation of the ophthalmologic apparatus 1 (end).

  The main control unit 211 creates a blood vessel map representing the distribution of the arteries and the distribution of the veins in the fundus oculi Ef based on the determination results for the plurality of target blood vessels obtained in step S10, and creates the blood vessel map formed in step S2. It can be displayed on the display unit 241 together with the contrast image. In the blood vessel map, the artery region and the vein region are presented in different colors. For example, the artery region is displayed in a warm color, and the vein region is displayed in a cool color.

  FIG. 8 schematically illustrates an example of a blood vessel map according to the embodiment.

  In the blood vessel map M, an artery region AM represented in red and a vein region VM represented in blue are depicted.

  For example, the main control unit 211 can display the blood vessel map and the front angiographic image in a superimposed manner. In this case, the blood vessel map can be displayed while being superimposed on the front angiographic image while displaying the front angiographic image as a monochrome image.

  For example, the main control unit 211 can display a blood vessel map and a front angiographic image side by side.

  For example, the main control unit 211 can switch display / non-display of a blood vessel map and / or switch display / non-display of a front angiographic image.

  In some embodiments, the user is configured to be able to perform an operation on the operation unit 242 to switch the display mode of the blood vessel map. For example, the user performs an operation for displaying only the artery region, an operation for displaying only the vein region, an operation for switching display / non-display of the artery region, and an operation for switching display / non-display of the vein region. And so on.

  For example, when the user performs an operation for displaying only the artery region while the blood vessel map M illustrated in FIG. 8 is displayed, the main control unit 211 presents only the artery region AM in the blood vessel map M. The displayed artery map M1 is displayed on the display unit 241 instead of the blood vessel map M (see FIG. 9A).

  When the user performs an operation for displaying only the vein region while the blood vessel map M shown in FIG. 8 is displayed, the main control unit 211 presents only the vein region VM in the blood vessel map M. The displayed vein map M2 is displayed on the display unit 241 instead of the blood vessel map M (see FIG. 9B).

  When the user performs an operation to display only the vein region while the artery map M1 is displayed, the main control unit 211 causes the display unit 241 to display the vein map M2 instead of the artery map M1. You may. Conversely, when the user performs an operation for displaying only the artery region while the vein map M2 is displayed, the main control unit 211 displays the artery map M1 on the display unit 241 instead of the vein map M2. May be.

  In an arbitrary operation example, the main control unit 211 can store the collected data, an arbitrary image (such as a frontal angiography image), a blood vessel map, and the like in the storage unit 212. In addition, the main control unit 211 can transmit collected data, an arbitrary image (such as a frontal angiography image), a blood vessel map, and the like to an external device by controlling a communication interface (not shown). In addition, the main control unit 211 can record collected data, an arbitrary image (such as a front angioplasty image), a blood vessel map, and the like on a recording medium by controlling a recording device (not shown).

<Action / Effect>
The functions and effects of the blood flow measurement device, the information processing device, the information processing method, and the program according to the embodiment will be described.

  A blood flow measurement device (ophthalmologic apparatus 1) according to some embodiments measures a blood flow of a living body using optical coherence tomography. The blood flow measurement device includes a data acquisition unit (the optical system from the objective lens 22 to the OCT unit 100 and the arithmetic control unit 200 in FIG. 1), a phase image forming unit (222), and a region specifying unit (blood vessel region specifying unit 231). ), A size specifying unit (blood vessel region size specifying unit 232), and an information generating unit (234). The data acquisition unit acquires time-series data by repeatedly scanning a cross section of the living body (the fundus oculi Ef) that intersects the blood vessel of interest. The phase image forming unit forms a plurality of time-series phase images in the cross section based on the time-series data. The region measuring unit specifies a blood vessel region in each of the plurality of phase images formed by the phase image forming unit. The size measuring unit specifies the size (area, perimeter, etc.) of the blood vessel region specified by the region specifying unit. The information generating unit generates information representing a temporal change in the size specified by the size specifying unit for a plurality of phase images.

  According to such a configuration, a phase image of a cross section intersecting the target blood vessel of the living body is formed using optical coherence tomography, a blood vessel region in the formed phase image is specified, and the size of the specified blood vessel region is determined. Since the information indicating the change with time is generated, it is possible to grasp the state of the target blood vessel without performing a complicated analysis process on the phase information included in the time-series data. Therefore, the blood flow information of the living body can be acquired by a simpler method.

  A blood flow measurement device according to some embodiments includes a feature amount calculation unit (234) that calculates a feature amount of a temporal change in size based on information generated by an information generation unit.

  According to such a configuration, since the characteristic amount of the temporal change in the size of the blood vessel region is calculated from the cross-sectional phase image, the state of the blood flow of the target blood vessel can be easily grasped from the calculated characteristic amount. Will be able to do it.

  In the blood flow measurement device according to some embodiments, the characteristic amount includes a period (T) of a temporal change in size, a difference (D) between a minimum value (Min) and a maximum value (Max) in the temporal change, It includes at least one of a ratio (R) between the minimum value and the maximum value, a time required for changing from the minimum value to the maximum value (T1), and a time required for changing from the maximum value to the minimum value (T2).

  According to such a configuration, the heart rate of a living body, information on whether there is a suspicion of a circulatory disease, and the like can be obtained very easily.

  A blood flow measurement device according to some embodiments includes a blood vessel determination unit (235) that determines whether a blood vessel of interest is an artery based on a difference between a minimum value and a maximum value over time.

  According to such a configuration, it is possible to very easily determine whether or not the target blood vessel is an artery without performing complicated analysis processing on the phase information.

  In the blood flow measuring devices according to some embodiments, the blood vessel determination unit determines that the target blood vessel is an artery when the difference is equal to or greater than a threshold.

  According to such a configuration, it is possible to determine whether or not the blood vessel of interest is an artery by simple threshold processing.

  In the blood flow measurement devices according to some embodiments, the size specifying unit specifies the area or the perimeter of the blood vessel region specified by the region specifying unit.

  According to such a configuration, since information indicating a temporal change of the area or the perimeter of the blood vessel region in the phase image is generated, blood flow information of a living body can be obtained by a very simple process. Become like

  An information processing apparatus (arithmetic control unit 200) according to some embodiments includes a phase image forming unit (222), a region specifying unit (blood vessel region specifying unit 231), and a size specifying unit (vascular region size specifying unit 232). And an information generation unit (234). The phase image forming unit uses the optical coherence tomography to repeatedly scan a cross section that intersects a target blood vessel of a living body (fundus Ef) based on time-series data obtained by repeatedly scanning the cross-section. To form The region specifying unit specifies a blood vessel region in each of the plurality of phase images formed by the phase image forming unit. The size specifying unit specifies the size (area, perimeter, etc.) of the blood vessel region specified by the region specifying unit. The information generating unit generates information representing a temporal change in the size specified by the size specifying unit for a plurality of phase images.

  According to such a configuration, a phase image of a cross section intersecting the target blood vessel of the living body is formed using optical coherence tomography, a blood vessel region in the formed phase image is specified, and the size of the specified blood vessel region is determined. Since the information indicating the change with time is generated, it is possible to grasp the state of the target blood vessel without performing a complicated analysis process on the phase information included in the time-series data. Therefore, it is possible to provide an information processing apparatus capable of acquiring blood flow information of a living body by a simpler method.

  An information processing method according to some embodiments includes a phase image forming step, a region specifying step, a size specifying step, and an information generating step. The phase image forming step is based on time-series data obtained by repeatedly scanning a cross section intersecting a target blood vessel of a living body (fundus Ef) using optical coherence tomography. To form The region specifying step specifies a blood vessel region in each of the plurality of phase images formed in the phase image forming step. The size specifying step specifies the size of the blood vessel region specified in the region specifying step. The information generating step generates information representing a temporal change of the size specified in the size specifying step for the plurality of phase images.

  According to such a method, a phase image of a cross section intersecting a target blood vessel of a living body is formed using optical coherence tomography, a blood vessel region in the formed phase image is specified, and the size of the specified blood vessel region is determined. Since the information indicating the change with time is generated, it is possible to grasp the state of the target blood vessel without performing a complicated analysis process on the phase information included in the time-series data. Therefore, the blood flow information of the living body can be acquired by a simpler method.

  An information processing method according to some embodiments includes a feature amount calculating step of calculating a feature amount of a temporal change in size based on information generated in the information generating step.

  According to such a method, since the characteristic amount of the temporal change in the size of the blood vessel region is calculated from the cross-sectional phase image, the state of the blood flow of the target blood vessel can be easily grasped from the calculated characteristic amount. Will be able to do it.

  An information processing method according to some embodiments determines whether or not a blood vessel of interest is an artery based on a difference (D) between a minimum value (Min) and a maximum value (Max) in a temporal change.

  According to such a method, it is possible to very easily determine whether or not the blood vessel of interest is an artery without performing complicated analysis processing on the phase information.

  In the information processing method according to some embodiments, the blood vessel determination step determines that the target blood vessel is an artery when the difference is equal to or greater than a threshold.

  According to such a method, it is possible to determine whether or not the blood vessel of interest is an artery by simple threshold processing.

  In the information processing method according to some embodiments, the size specifying step specifies an area or a perimeter of the blood vessel region specified in the region specifying step.

  According to such a method, since information indicating a temporal change of the area or the perimeter of the blood vessel region in the phase image is generated, blood flow information of a living body can be acquired by a very simple process. Become like

  A program according to some embodiments causes a computer to execute each step of the information processing method described in any of the above.

  According to such a program, a phase image of a cross section that intersects a target blood vessel of a living body is formed using optical coherence tomography, a blood vessel region in the formed phase image is specified, and the size of the specified blood vessel region is determined. Since the information indicating the change with time is generated, it is possible to grasp the state of the target blood vessel without performing a complicated analysis process on the phase information included in the time-series data. Therefore, the blood flow information of the living body can be acquired by a simpler method.

  It is possible to create a computer-readable non-transitory recording medium that records the program according to any of the embodiments. The non-transitory recording medium may be in any form, and examples include a magnetic disk, an optical disk, a magneto-optical disk, and a semiconductor memory.

  The embodiment described above is merely an example of the present invention. Those who intend to implement the present invention can arbitrarily make modifications (omission, substitution, addition, etc.) within the scope of the present invention.

1 Ophthalmic apparatus 100 OCT unit 210 Control unit 211 Main control unit 220 Image forming unit 221 Tomographic image forming unit 222 Phase image forming unit 230 Data processing unit 231 Vessel region specifying unit 232 Vascular region size specifying unit 233 Information generating unit 234 Feature amount calculation Unit 235 blood vessel determination unit Ef fundus

Claims (13)

A blood flow measuring device that performs blood flow measurement of a living body using optical coherence tomography,
A data acquisition unit that acquires time-series data by repeatedly scanning a cross section that intersects a target blood vessel of a living body,
Based on the time-series data, a phase image forming unit that forms a plurality of time-series phase images in the cross section,
An area specifying unit that specifies a blood vessel area in each of the plurality of phase images formed by the phase image forming unit,
A size specifying unit that specifies the size of the blood vessel region specified by the region specifying unit,
An information generating unit that generates information indicating a temporal change in the size specified by the size specifying unit for the plurality of phase images,
A blood flow measuring device including: The blood flow measurement device according to claim 1, further comprising a feature amount calculation unit that calculates a feature amount of the size change over time based on the information generated by the information generation unit. The feature amount is a cycle of the temporal change of the size, a difference between a minimum value and a maximum value in the temporal change, a ratio between the minimum value and the maximum value, and a change from the minimum value to the maximum value. The blood flow measuring device according to claim 2, further comprising at least one of a time required and a time required for changing from the maximum value to the minimum value. The blood vessel determination part which determines whether the said blood vessel of interest is an artery based on the difference between the minimum value and the maximum value in the said time-dependent change is included. The Claim 2 or Claim 3 characterized by the above-mentioned. Blood flow measurement device. The blood flow measurement device according to claim 4, wherein the blood vessel determination unit determines that the blood vessel of interest is an artery when the difference is equal to or greater than a threshold. The blood flow measuring device according to any one of claims 1 to 5, wherein the size specifying unit specifies an area or a circumference of the blood vessel region specified by the region specifying unit. Based on time-series data obtained by repeatedly scanning a cross section intersecting the blood vessel of interest using optical coherence tomography, a phase image forming unit that forms a plurality of time-series phase images in the cross section,
An area specifying unit that specifies a blood vessel area in each of the plurality of phase images formed by the phase image forming unit,
A size specifying unit that specifies the size of the blood vessel region specified by the region specifying unit,
An information generating unit that generates information representing a temporal change in the size specified by the size specifying unit for the plurality of phase images,
An information processing device including: Based on time-series data obtained by repeatedly scanning a cross section that intersects the blood vessel of interest using optical coherence tomography, a phase image forming step of forming a plurality of time-series phase images in the cross section,
An area specifying step of specifying a blood vessel area in each of the plurality of phase images formed in the phase image forming step,
A size specifying step of specifying the size of the blood vessel region specified in the region specifying step,
An information generating step of generating information representing a temporal change in the size specified in the size specifying step for the plurality of phase images;
An information processing method including: The information processing method according to claim 8, further comprising: a feature amount calculating step of calculating a feature amount of the change with time of the size based on the information generated in the information generating step. The blood vessel determination step of determining whether or not the blood vessel of interest is an artery based on a difference between a minimum value and a maximum value in the temporal change. Information processing method. The information processing method according to claim 10, wherein the blood vessel determination step determines that the target blood vessel is an artery when the difference is equal to or greater than a threshold. The information processing method according to any one of claims 8 to 11, wherein the size specifying step specifies an area or a perimeter of the vascular region specified in the region specifying step.   A program for causing a computer to execute each step of the information processing method according to any one of claims 8 to 12.

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